Move keyframes from timeline?
It is not possible to move keyframes directly in the timeline window.

But in the dopesheet, you can select all the keyframes of an animated object at once, by click the top one, in the master channel :



You can still box select with B like @Cosifa said, and move, scale, or duplicate them.

Edit: Oh! and you can always re-arrange your window panes as you want, to suits your needs if you want a big 3D view and a little dopesheet window at the bottom screen ;)